Voltage-regulator.



L. W. THOMPSON.

VOLTAGE REGULATOR.

APPLICATION FILED APR-111914.

Patented June 27, 1916.

U TED STATES PATENT OFFICE.

LOUIS WILLARD THOMPSON, OF BUFFALO, NEW YORK, ASSIGNOR, BY MESNE ASSIGN- MEN'I'S, TO GENERAL ELECTRIC COMPANY A CORPORATION OF NEW YORK.

VOLTAGE-REGULATOR.

To all whom it may concern Be it known that I, LOUIS WILLARD THOMPSON, a citizen of the United States, residing at Buffalo, in the-county of Erie and State of New York, have invented a new and useful Improvement in Voltage- Regulators, of which the following is a specification.

This invention relates to voltage regulators of the kind having a solenoid or other electrically controlled actuating device which is influenced by changes in the voltage and which actuates means for counteracting any changes in the voltage.

Voltage regulators as heretofore constructed are caused to operate by a change in the "oltage, in the system of which the voltage is to be kept constant. If a sudden change ofgconsiderable magnitude takes place in the current supplied by a system, such, for example, as results from the closing of the armature circuit of an elevator motor, the voltage of the system has a tendency to drop suddenly and this tendency cannot be at once entirely counteracted by the regulator, since an interval of time must elapse before the change in the voltage can cause the regulator to counteract this change. In case of a change of considerable magnitude in current, this small interval of time is sufficient to permit a noticeable change to take place in the volt-- age. Consequently these regulators, although satisfactory under many conditions cannot maintain the voltage absolutely constant in case of a sudden change of conv siderable-magnitude in the current supply of the system.

The object of this invention is to produce means which cooperate with a switch or other circuit controlling device and with the voltage regulator insuch a manner that the adjustment of the regulator is temporarily changed and the voltage regulator is enabled to anticipate the change in the voltage due to ,1 the opening or closing of the switch or other device, and thereby eliminate the interval of time which ordinarily elapses between a sudden change in the voltage and the bringing of the voltage back to normal by the regulator.

In the accompanying drawings: Figure 1 shows diagrammatically a compensating means for voltage regulators embodying the invention; Fig. 2 is a perspective view of Specification of Letters Patent.

Application filed April 1, 1914. Serial No. 828,753.

a switch of modified construction which may be employed in connection with the compensatlng means; Fig. 3 shows a modified form of compensating unit.

Briefly stated, the invention consists in providing means actuated by the movable member of a switch or other circuit openng or closing device for changing the adustment of thevoltage regulator, as for example by inserting a compensating unit in the circuit of the control solenoid thereof to thereby cause theregulator to raise or lower the voltage of a system, as may be desired, before the switch is actually opened or closed, so that the voltage regulator will be enabled to anticipate a change in voltage caused by the opening or' 'closing of the switch and to offset this change as soon as it occurs, together with means for determining the period of this corrective action.

The compensating means are shown in the accompanying drawings as applied to a switch and are brought into operation by the closing of the switch to cause the voltage regulator to increase the voltage of the circuit, but it will be understood that it is not thereby intended to limit the use of this invention, to increasing the voltage, since the compensating means can equall well be operated by the opening of a switch or the like to prevent the voltage from suddenly increasing beyond the desired normal value.

In the accompanying drawing, I have illustrated a system, a, a, which may be supplied by a generator S provided with a field winding 8. In circuit with this field winding is the usual adjustable resistance 8'. Connected across the mains a, a of the system of distribution, by means of the conductors a a, is a control solenoid, or electromagnetic winding, A This may be taken to indicate the actuating device of a voltage regulator of any desired construction. One construction of regulator is that indicated in the drawing, in which the winding A is used to control the movement of the core B attached to the lever B. Carried upon this lever is one of the contacts 7', and the lever is spring-pressed in a direction to hold the contacts closed. These contacts will preferably be connected so as to short-circuit the resistance 8', and by opening and closing the contacts in response to the voltage of the generator, this voltage may be maintained constant. A fixed resistance a will commonly be connected in the circuit of the control solenoid A, to reduce the current flowing in the solenoid, and will usually be of such a magnitude that it constitutes a large pro rtion of the resistance of the circuit. A1 of these parts may be of any-usual or desired construction and of themselves constitute no part of this invention.

C re resents the armature of a motor which is connected to the lines a a of the system, for instance, by conductors d d and a switch or circuit controlling device D which comprises a movable member or arm d and a fixed contact (1, which, as shown, is mounted on an insulating support d. The controlling device may be adapted to be operated by hand, or may form a part of an automatic starter. The closing of the controlling device, in the construction shown, permits a momentary current of con siderable magnitude to pass through thearmature C, and in order to prevent a drop in the voltage of the system which would otherwise be caused by closing the device, the following means are employed: The circuit of the solenoid or actuating device of the voltage regulator includes a compensating unit E, which may be a separate resistance, as shown in the drawings, and if desired, it can be made adjustable, as indicated. The compensating unit is adapted to be rendered active or inactive, as may be desired, in any suitable manner, for example, by short circuiting the same. In the construction shown, the compensating unit is normally short circuited, as will be here inafter described. When the compensating unit is placed in the solenoid circuit 1t changes the adjustment of the re lator and produces the same effect u on t e solenoid as would a drop in the V0 tage of the system; viz., it decreases the flow of current throu h the solenoid and hence decreases the efl iactive ampere turns thereof and causes the voltage regulator to operate to raise the voltage of the system.

Any suitable means may be employed to render the compensating unit active, 11. e., to

place the same in the circuit just prior to the closing of the controlling device D, the following means being shown in, the drawings: Themovable member d of the controlling device is provided with a brush or spring contact f, which, when the device is open, engages with a stationary contact plate F, which may be mounted on the insulating support cl of the controlling device. This contact plate F is connected by a conductor f to a contact 9 of a switch G, the movable member g of which is yieldingly held in engagement with the contact 9, for example, by a spring g. The movable member of the switch G is connected by a conductor g to one side of the compensat' unit in the solenoid circuit. Thus when the controlling device D is open the current flowing in the solenoid circuit, instead of the circuit which short circuits the compensating unit. Thus during the closing movement of the movable arm (1' the compensatin unit is momentarily inserted into the so enoid circuit of the voltage regulator and acts as heretofore explained, to raise the voltage, so that when the movable arm d engages with the contact d" the voltage of the system will be rising to meet the drop which is caused by the closing of the armature circuit.

When the controlling device D is closed the compensating unit is a in short circuited, preferably by the fo lowing means: An electroma et I is arranged to move the movable member 9 of the switch G,-which forms an armature for the electromagnet, against the action of the spring 9' into engagement with a contact 1'. The magnet receives its power through conductors i a" connected to opposite sides of the motor armature C, and a resistance 1" may be inserted into the magnet circuit if dedred. The contact i is connected to the line a by a conductor 11. Hence when the movable member of the switch G engages the contact circuited through conductor 5, switch G and conductor g. By means of this arrangement the compensating unit will be rendered ineffective by the action of the magnet I when the motor armature generates sufficient counter-electromotive force to energize the magnet and the original adjustment of the regulator restored.

If desired, the compensating unit may comprise a plurality of turns of wire E (see Fig. 3) upon the solenoid or other actuating device of the regulator. These turns will be arranged to be rendered active and inactive in any suitable manner so as to produce the same efiect upon the solenoid as would a drop .in the voltage of the system. Because of the fact that the resistance a constitutes a large proportion of the resistance of the circuit a, a, including the solenoid A, a change in the number of turns of the solenoid will produce an almost exactly A, in order that the same arrangement 01 the switches D and G may be employed.

From this description, it will be seen that, when the short-circuit around the unit E is removed by the closure of the switch D,

the unit will be rendered active to reduce the effective ampere turns of the regulating solenoid, and that it will be later rendered inactive by the switch G in the same manner as was the unit E.

The interval of time which should elapse between the influencing of the voltage regulator by the compensating unit and the 010s ing of the switch or controlling device D varies according to the increase in current caused by the closing of the controlling device. For a large increase in current this time should be greater than for a smaller increase. The length of this time can be controlled by causing the brush or contact 7'' of the movable arm d to move out of engagement with the contact plate F earlier or later during the circuit closing movement of the arm (1 This can be accomplished by various means, two constructions being shown for this purpose.

In the construction shown in Fig. 1, the brush or spring contact f is adjustable on the movable arm (I of the'controlling device D in the direction of movement of the arm, the brush being secured by means of a set screw is. By adjusting the brush on the movable arm the interval of time between the breaking of' the contact between the brush and contact plate F and the engagement of the movable arm d with the contact (i can be varied as desired. In the construction shown in Fig. 2, this is accomplished by making the contact plate L triangular in form and mounting the same on an insulating plate L which is adjustable relatively to the insulating support d*. The insulating plate L is slidably mounted in a guide-way l on the support at and is ad justed by means of a screw I mounted on the support and having a threaded engagement with the insulating panel. In this construction a brush or contact spring Z is fixed on the contact arm d By adjusting the insulating plate the distance between the point at which the brush Z leaves the contact plate L, and the contact d can be increased or decreased and consequently the time during which the compensating unit influences the voltage regulator can be varied.

-On the return movement of the switch member d the compensating unit will not influence the voltage regulator to raise the voltage of the system since the counter-electromotive force of the motor C will keep the magnet I energized until the switch or controlling member is again opened and contact between the brush f and the contact plate has been established.

The compensating unit can be arranged to cooperate with any. switch or circuit-controlling device in a circuit, so that the volt-' age regulator is thereby enabled to maintain a substantially constant voltage in spite of great fluctuations in the current flowing in the circuit. v

I claim as my invention:

1. In combination, a generator, a regulator therefor adjusted to respond to predetermined changes in generator voltage for controlling the voltage of said generator,-an electric motor, means for connecting the same to said generator, means controlled thereby for changing the adjustment of said regulator as said connecting means is closed, and means for restoring the original adjustment after the motor is started.

2. In combination, a generator, a regulat'or, including an electromagnetic winding, controlling the voltage of said generator, an electric'motor, means for connecting the same to said generator, thereby tendingto change the voltage of the generator, means responsive to the movement of said connecting means arranged to vary the effective ampere turns of said winding so as to counteract the eflect of said increased load upon the voltage of said generator, and means for rendering said varying means inefiective when said connecting means is in approximately its extreme positions.

3. In combination, a generator, a regulator, including an electromagnetic winding, controlling the voltage of said generator, an electric motor, means for connecting the same to said generator, thereby tending to change the voltage of said generator, means comprising a compensating unit for varying the effective ampere turns of said winding so as to counteract the effect of saidv increased load upon the voltage of said generator, means responsive to the move ment of said connecting means for shortcircuiting said unit when said connecting means is open, and for removing said shortcircuit prior to the closure of said connecting means, and means for again short-circuiting said unit after said connecting means has been closed.

4. The combination with a source of supply, a supply circuit, a voltage regulator having an actuating device responsive to the voltage of said source of supply, and a controlling device having a movable memberadapted when in its closed position to increase the flow of current in said circuit,

of a compensating unit adapted to be placed in the circuit of said actuating device, means ting unit in the circuit of said actuating devlce, and means for varying "the length of the movement of said movable member during which the compensating unit is inserted into the circuit of said actuating device.

5. The combination with a source of supply, a supply circuit, a voltage regulator havin an actuating device responsive to the v0 tage of said source of suppl and a controlling device having a movab e membeli adapted when in its closed position to increase the flow of current in said circuit, of a compensating unit in the'circuit of said actuating device, a contact engaged by said movable member when in its open 0- sition, a contact with which said mova le member engages when in its closed position, means for short-circuiting said compensating unit when said movable member engages either of said contacts, and means for varying the distance between said contacts.

6. The combination with a source of supply, a supply circuit, a voltage regulator having an actuating device responsive to the voltage of said source of supply, and a controlling device having a movable member adapted when in its closed position to increase the flow of current in said circuit, of a compensating unit in the circuit of said actuating device, a contact engaged by said movable member when in its open position, electrical connections including said movable member and said contact and a switch for short-circuiting said compensating unit when the movable member is in its open position, and means for actuating said switch to short circuit said compensating unit when the movable member is in its closed position. i

7. 'The combination with a source of supply, a supply circuit, a voltage regulator having an actuating device responsive to the voltage of said source of supply, a circuit closing device having a movable member adapted to increase the flow of current in said supply circuit, of a compensating unit in the circuit of said actuating device, a circuit including said movable member for short-circuiting said compensatingv unit when said movable member is 1n its open position, a switch in said circuit, and means for actuating said switch to short circuit said compensating unit when said movable member is in its closed position.

8. The combination with a source of supply, a supply circuit, a voltage regulator having an actuating device responsive to the voltage of said source of supply, a power consuming device, a circuit closing device having a movable member adapted when -in its closed position to cause current: to

flow from said supply circuit to said power consuming device, of a compensating unit in the circuit of said actuating. device, a

circuit, including-said movable member, for short-circuiting said compensating unit when said movable member is in its open position, said circuit being opened bythe movement of said member to its closed position, a switch in said circuit, and a magnet which is actuated when current is flow' in said ower consuming device to actuate said to short circuit said compensating and arranged to place it in active relation to the circuit of said actuating device, means for regulating the effect of said compensating unit on said regulator, and means independent of said controlling device for subsequently rendering said unit ineflective.

10. The combination with a source of supply, a supply circuit, a voltage regulator having an actuating device I responsive to the volta of said source of supply, and a controlling device which produces a change in the flow of current in said circuit, of a com nsating unit. of a variable resiftance, connected inthe.

circuit of said actuating device, means actuated by said controlling device to place said compensating unit in active relation to the circuit of sald actuating device, to cooperate with the voltage regulator to counteract the effect on the voltage of the system of said change in current, and means independent of said controlling device arranged to subsequently short-circuit said resistance.

11. The combination with a source of supply, a supply circuit, a voltage regulator having an actuating device responsive to the voltage of said source of supply, and a controlling device having a movable member adapted when in its closed position to increase the flow of current in said circuit, of a compensating unit in the circuit of said actuating device, a brush on said movable member and adjustable thereon in the direction of movement of the member, a contact adapted to be engaged by said brush, a circuit including said brush and contact for short-circuiting said compensating unit when the movable member is'in its open position, and a circuit for short-circuitin said compensating unit when the movab 0 member is in its closed position, whereby, with uniform rate Ill of motion of said member,- the time during which the compensating unit is not short circuited can be varied by adjusting said brush.

12. In combination,- a generator, a supply circuit connected thereto, a dynamoelectric machine arranged to be supplied with power from said supply circult, a switch for connectingsaid machine in circuit, a voltage regulator comprising a winding responslve to the voltage of said generator, and arranged to hold said voltage constant, a compensating unit connected in circuit with said winding, means responsive to the movement of said switch for shortcircuiting said unit when said switch is open said means being arranged to open said short-circuit prior to the closure of said switch, and means responsive to the terminal voltage of said machine for subsequently short-circuiting said unit after said machine has been connected in circuit.

Witness my hand, this 30th day of March, 1914 LOUIS WILLARD THOMPSON Witnesses:

F. E. Pnocnuow, A. L. MCGEE. 

